Ultrafast detection of pharmaceuticals in biological matrices using Coated Blade Spray Mass Spectrometry

Food safety control requires fast testing analytical methodologies since a large number of samples have to be analyzed. In many cases, short turn-over times are requested, especially concerning perishable products, like food-producing animal meat. In these animal-derived products, food-safety laboratories test for residues of prohibited or regulated pharmaceuticals. The current workflow compromises sampling of matrices of slaughtered animals, transportation of these samples to a centralized laboratory, screening of the samples and performance of confirmatory analysis for suspect findings. Screening is often performed using rapid tests, like lateral flow or microbiological assays. While confirmatory analyses are performed using chromatographic separation techniques in combination with mass spectrometry (MS). These latter techniques would ideally also be used for screening, as these instruments are more sensitive and selective and allow identification/confirmation of an individual substance. However, the current MS methods are time-consuming, require a lot of organic solvents, and do not enable direct or fast detection. Ambient ionization mass spectrometry (AIMS) techniques allow rapid, real-time, and in-situ mass spectrometric analysis while, in most cases, keeping organic solvent use at a minimum [1]. The AIMS technique Coated Blade Spray Mass Spectrometry (CBS-MS) has readily demonstrated great potential in food-safety and medical fields [2-3] due to the combination of a biocompatible sorbent material coated with a conductive metal surface. This sorbent layer binds and enriches the analytes of interest, while the conductive surface allows for electrospray ionization using a high voltage. In short, CBS-MS devices are placed in the sample, matrix artefacts are washed off, and blades are placed in front of the mass spectrometer. Applying a small volume of desolvation/ionization solvent on the coated material results in extraction, and applying at the same time a high voltage generates electrospray from the tip of the blade, all within 1 minute. Here, the methodology developed using CBS-MS and results obtained on kidney organs from slaughtered animals to facilitate ultrafast detection and identification of antibiotic residues are presented.